Chapter V: Part II: Gas-Light (1)

PRELIMINARY OBSERVATION.

A new art of procuring artificial light, which consists in burning the gazeous fluid obtained by distillation from common pit-coal, has of late engaged the attention of the public, under the name of _gas-light_.

The encouragement that has been given for some years past by the legislature to this system of lighting, has induced certain individuals to apply the coal-gas light for the illumination of streets, houses, roads, and public edifices. And it is sufficiently known that a company has been incorporated by charter under the name of the “_Gas Light and Coke Company_,” to apply this new art of procuring light, by way of experiment, on a large scale, in lighting the streets of the metropolis.[10]

[10] An Act for granting certain powers and authorities to a company
to be incorporated by charter, called the “Gas Light and Coke
Company,” for making inflammable air for the lighting of the streets
of the metropolis, &c.--Session 1810, 50th Geo. III.

The power and authorities granted to this corporate body are very restricted and moderate. The individuals composing it have no exclusive privilege; their charter does not prevent other persons from entering into competition with them. Their operations are confined to the metropolis where they are bound to furnish not only a stronger and better light to such streets and parishes as chuse to be lighted with gas, but also at a cheaper price than shall be paid for lighting the said streets with oil in the usual manner. The corporation is not permitted to traffic in machinery for manufacturing or conveying the gas into private houses, their capital or joint stock is limited to 200,000_l._ and His Majesty has the power of declaring the gas-light charter void, if the company fail to fulfil the terms of it.

THEORY OF THE COMBUSTION OF COAL IN ELUCIDATION OF THE NATURE AND PRODUCTION OF GAS LIGHT.

Pit-coal exists in this island in strata, which, as far as concerns many hundred generations after us, may be pronounced inexhaustible; and is so admirably adapted, both for domestic purposes and the uses of the arts, that it is justly regarded as a most essential constituent of our national wealth. Like all other bituminous substances, it is composed of a fixed carbonaceous base or bitumen, united to more or less earthy and saline matter constituting the ashes left behind when this substance is burnt. The proportions of these parts differ considerably, in different kinds of coal; and according to the prevalency of one or other of them, so the coal is more or less combustible, and possesses the characters of perfect pit-coal; and by various shades, passes from the most inflammable canel-coal, into blind, Kilkenny, or stone-coal; and, lastly, into a variety of earthy or stony substances; which, although they are inflammable, do not merit the appellation of coal.

Every body knows that when pit-coals are burning in our grates, a flame more or less luminous issues from them, and that they frequently emit beautiful streams of flame remarkably bright. But besides the flame, which is a peculiar gas in the state of combustion, heat expels from coal an aqueous vapour, loaded with several kinds of ammoniacal salts, a thick viscid fluid resembling tar, and some gases that are not of a combustible nature. The consequence of which is, that the flame of a coal-fire is continually wavering and changing, both in shape, as well as brilliance and in colour, so that what one moment gave a beautiful bright light, in the next, perhaps, is obscured by a stream of thick smoke.

But if coals, instead of being suffered to burn in this way, are submitted to distillation in close vessels, all its immediate constituent parts may be collected. The bituminous part is melted out in the form of tar. There is disengaged at the same time, a large quantity of an aqueous fluid, contaminated with a portion of oil, and various ammoniacal salts. A large quantity of carburetted hidrogen, and other uninflammable gases, make their appearance, and the fixed base of the coal remains behind in the distillatory apparatus in the form of a carbonaceous substance, called coke.

All these products may be separately collected in different vessels. The carburetted hidrogen, or coal-gas, may be freed from the non-inflammable gases, and afterwards forced in streams out of small appertures, which, when lighted, may serve as the flame of a candle to illuminate a room or any other place. It is thus, that from pit-coal a native production of this country, we may procure a pure, lasting, and copious light; which, in other cases, must be derived from expensive materials, in part imported from abroad.

It is chiefly upon the power of collecting the products afforded by coal, with convenience and cheapness, that the promoters of the gas-light illumination found their claims to public encouragement. They conceive that the flame which pit-coal yields, as it is now consumed, is turned to very little advantage: it is not only confined to one place, where a red heat is more wanted than a brilliant flame, but it is obscured, and sometimes entirely smothered, by the quantity of incombustible materials that ascend along with it and pollute the atmosphere.

That much inflammable matter is thus lost, is evident from facts that come under our daily observation. We often see a flame suddenly burst from the densest smoke, and as suddenly disappear; and if a light be applied to the little jets that issue from the bituminous parts of the coal, they will catch fire, and burn with a bright flame. A considerable quantity of a gazeous fluid, capable of affording light and heat continually escapes up the chimney, whilst another part is occasionally ignited, and exhibits the phenomena of the flame and light of the fire.

The theory of the production of gas-light is therefore analogous to the action of a lamp or candle. The wick of a candle being surrounded by the flame, is in the same situation of the pit-coal exposed to distillation. The office of the wick is chiefly to convey tallow, by capillary attraction, to the place of combustion. As it is decomposed into carburetted hidrogen gas it is consumed and flies off, another portion succeeds; and in this way a continued current of tallow and maintenance of flame are effected. See page 15.

The combustion of oil by means of a lamp depends on similar circumstances. The tubes formed by the wick serve the same office as a retort placed in a heated furnace through which the inflammable liquid is transmitted. The oil is drawn up into these ignited tubes, and is decomposed into carburetted hidrogen gas, and from the combustion of this gas the illumination proceeds. See p. 15. What then does the gas-light system attempt? Nothing more than to generate, by means of sufficient furnaces and a reservoir of sufficient capacity, desired quantities of the gas, which is the same material of the flame of candles or lamps; and then by passing it through pipes to any desired distance, to exhibit it there at the mouths of the conducting tubes, so that it may be ignited for any desired purpose. The only difference between this process and that of an ordinary candle or lamp, consists in having the furnace at the manufactory, instead of its being in the wick of the candle or lamp--in having the inflammable material distilled at the station, instead of its present exhibitions in oil, wax, or tallow, and then in transmitting the gas to any required distance, and igniting it at the orifice of the conducting pipe instead of igniting it at the apex of the wick. The principle is rational, and justified by the universal mode in which all light is produced. Indeed, this discovery ranks among the numerous recent applications of chemical science to the purposes of life, which promise to be of the most general utility.

It is evident from the outline here given of the production and application of coal-gas, that all the uses of pit-coal are not exhausted; it will be sufficient to observe, that the complete analysis of coal, which has been hitherto confined to the laboratory of the chemist, requiring skill and nicety in the operator, and attended with great trouble and expence, is now so far simplified, that many chaldrons of coals may be decomposed by one gas-light apparatus in the space of six hours, and all the component parts produced in their most useful shape, at an expence out of all proportion below the value of the products.

SKETCH OF THE RISE AND PROGRESS OF THE DISCOVERY AND APPLICATION OF COAL-GAS, AS A SUBSTITUTE FOR PROCURING ARTIFICIAL LIGHT.

To assist the reader in comprehending the nature and object of substituting coal-gas for tallow or oil, for the purpose of obtaining light, it may be proper to touch slightly upon the successive discoveries that have been made as to the decomposition of coal, and the application of its different ingredients. Such a sketch will add to the many examples that occur in the history of science and art, showing the slow progress of mankind in following up known principles, or extracting from acknowledged facts every possible advantage.

In the Philosophical Transactions of the Royal Society, V. XLI. so long ago as the year 1739, is recorded a paper, exhibiting an account of some experiments made by Dr. James Clayton, from which it appears that the inflammable nature of coal-gas was then already known. Dr. Clayton having distilled Newcastle coal, obtained, as products of the process, an aqueous fluid, a black oil, and an inflammable gas, which he caught in bladders, and by pricking these he was enabled to inflame the gas at pleasure.

It is further known, that in the beginning of the last century, Dr. Hales[11] on submitting pit-coal to a chemical examination, found, that during the ignition of this fossil in close vessels, nearly one-third of the coal became volatilized in the form of an inflammable vapour. Hence the discovery of the inflammable nature of coal-gas can no longer be claimed by any person now living.

[11] Vegetab. Statics, vol. I.

In the year 1767, the Bishop of Llandaff[12] examined the nature of the vapour and gazeous products evolved during the distillation of pit-coal. This learned philosopher noticed, that the volatile product is not only inflammable as it issues from the distillatory vessel, but that it also retained its inflammability after having been made to pass through water, and suffered to ascend through two high curved tubes. The solid matters obtained by this venerable prelate, were, an aqueous ammoniacal fluid, a tenaceous oil, resembling tar, an ammoniacal liquor, and a spongy coal, or coke.

[12] Watson’s Chemical Essays, vol. II.

The first discovery and application of the use of coal-gas for the purpose of illumination is claimed by Mr. Murdoch.

Dr. W. Henry of Manchester, has published the following account[13] of this discovery.

[13] Thompson’s System of Chemistry, vol. I. p. 52.

“In the year 1792, at which time Mr. Murdoch resided at Redruth, in Cornwall, he commenced a series of experiments upon the quantity and quality of the gases contained in different substances. In the course of these he remarked, that the gas obtained by distillation from coal, peat, wood, and other inflammable substances, burnt with great brilliancy upon being set fire to; and it occurred to him, that by confining and conducting it through tubes, it might be employed as an economical substitute for lamps and candles. The distillation was performed in iron retorts, and the gas conducted through tinned iron and copper tubes to the distance of 70 feet. At this termination, as well as at intermediate points, the gas was set fire to, as it passed through apertures of different diameters and forms, purposely varied with a view of ascertaining which would answer best. In some the gas issued through a number of small holes like the head of a watering pan; in others it was thrown out in thin long sheets; and again in others in circular ones, upon the principle of Argand’s lamp. Bags of leather and of varnished silk, bladders, and vessels of tinned iron, were filled with the gas, which was set fire to, and carried about from room to room, with a view of ascertaining how far it could be made to answer the purpose of a moveable or transferable light. Trials were likewise made of the different quantities and qualities of gas produced by coals of various descriptions, such as the Swansea, Haverfordwest, Newcastle, Shropshire, Staffordshire, and some kinds of Scotch coals.

“Mr. Murdoch’s constant occupations prevented his giving farther attention to the subject at that time; but he again availed himself of a moment of leisure to repeat his experiments upon coal and peat at Old Cumnock, in Ayrshire, in 1797; and it may be proper to notice that both these, and the former ones, were exhibited to numerous spectators, who, if necessary, can attest them. In 1798, he constructed an apparatus at Soho Foundry, which was applied during many successive nights to the lighting of the building; when the experiments upon different apertures were repeated and extended upon a large scale. Various methods were also practised of washing and purifying the air, to get rid of the smoke and smell. These experiments were continued, with occasional interruptions, until the epoch of the peace in the spring of 1802, when the illumination of the Soho manufactory afforded an opportunity of making a public display of the new lights; and they were made to constitute a principal feature in that exhibition.”

In the year 1803 and 1804, Mr. Winsor exhibited at the Lyceum in London the general nature of this new mode of illumination though the machinery for procuring, and the manner of purifying the gas, he kept a secret. He exhibited the mode of conducting the gas through the house, and a number of devices for chandeliers, lamps, and burners, by which it might be applied. Among these he proposed long flexible tubes suspended from the ceiling, or wall of the room, and at the end communicating with burners or lamps of different kinds. This gentleman showed also by experiment, that the flame of the gas-light, produced no smoke; that it was not so dangerous as the flame of candles or lamps; that it could not produce sparks; and that it was not so readily extinguished by gusts of wind or torrents of rain.

Mr. WINSOR’s display of gas-lights took place more than two years before Mr. MURDOCH’s priority of right was heard of.

In stating these facts I do not mean to say that Mr. MURDOCH derived the hint of applying the coal-gas from the previous exhibition of Mr. WINSOR, because it is quite within the bounds of probability that the ideas of Mr. MURDOCH may have arisen totally independent of all acquaintance with Mr. WINSOR’s.

The claims of invention, or the determination of the right of priority, concerns the public only so far as the honour and estimation of any useful discovery conferred on the inventor may induce other individuals to devote their talents to similar pursuits; by means of which, more discoveries may be made, and the subject of human invention become extended, or rendered more useful. For as the mere benefits which mankind may derive from any particular discovery, they are certainly more indebted to the person who first applied the discovery to actual practice, than to him who first made it, and merely illustrated it by barren experiments. Mr. WINSOR certainly pressed on the mind of the public with unremitted perseverance and diligence the extensive application of gas-light in the year 1802, but he made no new discovery with regard to the composition of coal; he did not even invent the mode of conducting the gas through tubes; and if he has pointed out the particulars of the process, he has made a very important, though not the most brilliant improvement in this line of business. Mr. WINSOR’s publications are, perhaps, but ill adapted to promote his cause; and the exaggerated calculation which the sanguine mind of a discoverer is naturally disposed to indulge in, have, to superficial observers, thrown an air of ridicule and improbability on the whole scheme of lighting with gas.

It may, however, be safely affirmed, that if the same facts had come forward, under the sanction of some great name in the chemical or philosophical world, the public incredulity would long since have been subdued; and the plan, which for many years has been struggling for existence, would have been eagerly adopted as a national object.

On the 18th of May, 1804, Mr. FREDERICK ALBERT WINSOR, took out a patent for combining the saving and purifying of the inflammable gas (for producing light and heat), the ammonia, tar, and other products of pit-coal, with the manufacture of a superior kind of coke (see Repertory, 2d Series, v. 172). And, lately, the same gentleman has taken out a second patent, for further improvements in these processes.

In the year 1805, Mr. NORTHERN, of Leeds, also directed the attention of the public to the application of coal-gas, as a substitute for tallow light, as will be seen by the following extract of the Monthly Magazine for April, 1805.

“I distilled in a retort, 50 ounces of pit-coal in a red heat, which gave 6 ounces of a liquid matter covered with oil, more or less fluid as the heat was increased or diminished. About 26 ounces of cinder remained in the retort; the rest came over in the form of air, as it was collected in the pneumatic apparatus. I mixed part of it with atmospherical air, and fired it with the electric spark with a tolerable explosion, which proves it to be hydrogene.--Whether any of the other gases were mixed with it, I did not then determine. In the receiver I found a fluid of an acid taste, with a great quantity of oil, and, at the bottom, a substance resembling tar.

“The apparatus I make use of for producing light is a refiner’s crucible, the top of which (after filling with coal) I close with a metal cover, luted with clay or other luting, so as to prevent the escape of the gas; a metal pipe is soldered into the cover, bent so as to come under the shelf in the pneumatic trough, over which I place a jar with a stop-cock and a small tube; the jar being previously filled with water, the crucible I place on the common or other fire as is most convenient; and as the heat increases in it, the gas is forced rapidly through the water into the jar, and regularly displaces it. I then open the cock and put fire to the gas, which makes its escape through the small tube, and immediately a most beautiful flame ensues, perfectly free from smoke or smell of any kind. A larger light, but not so vivid or clear, will be produced without passing the gas through water, but attended with a smoke somewhat greater than that of a lamp charged with common oil.

“I have great hopes that some active mechanic or chemist will, in the end, hit on a plan to produce light for large factories, and other purposes, at a much less expence, by the above or similar means, than is at present produced from oil.”

Soon afterwards, Mr. SAMUEL CLEGG[14] of Manchester, Engineer, communicated an account of his method of lighting up manufactories with gas-light to the Society of Arts, for which he received the silver medal.

[14] This gentleman is at present engineer to the Gas-Light Company.

Since that time, the application of gas-light has spread rapidly, and numerous manufactories and other establishments have been lighted by coal-gas.

In France, the application of gas-lights to economical purposes, was pointed out long before it was publicly introduced into this country. M. LE BON had a house fitted up in Paris, in the winter of 1802, so as to be entirely illuminated by gas-lights, which was seen by thousands with admiration; and had a _brevet d’invention_ (patent) granted to him by the French government, for the art of producing light from wood, ignited in close vessels.

Many other attempts have been made to derive advantage from the different ingredients of coal; but they are too obscure to merit particular enumeration.

In the year 1808, Mr. MURDOCH presented to the Royal Society his account of the application of gas-light, and was complimented with Count ROMFORD’s medal for the same.

The following statement is taken from Mr. MURDOCH’s paper.

“The whole of the rooms of the cotton mill of Mr. LEE, at Manchester, which is I believe the most extensive in the United Kingdom, as well as its counting-houses and store-rooms, and the adjacent dwelling house of Mr. LEE, are lighted with the gas from coal. The total quantity of light used during the hours of burning has been ascertained, by a comparison of shadows, (_see page 23_) to be about equal to the light which 2500 mould candles, of six to the pound, would give; each of the candles with which the comparison was made consuming at the rate of 4-10ths of an ounce (175 grains) of tallow per hour.

“The gas-burners are of two kinds: the one is upon the principle of the Argand lamp, and resembles it in appearance; the other is a small curved tube with a conical end, having three circular apertures or perforations, of about a thirtieth of an inch in diameter, one at the point of the cone, and two lateral ones, through which the gas issues, forming three divergent jets of flame, somewhat like a fleur-de-lis. The shape and general appearance of this tube has procured it, among the workmen, the name of the cockspur burner.

“The number of burners employed in all the buildings amounts to 271 Argand, and 653 cockspurs, each of the former giving a light equal to that of four candles of the description above-mentioned; and each of the latter a light equal to two and a quarter of the same candles; making therefore the total of the gas-light a little more than equal to that of 2500 candles, six to the pound. When thus regulated, the whole of the above burners require an hourly supply of 1250 cubic feet of the gas produced from cannel-coal; the superior quality and quantity of the gas produced from that material having given it a decided preference in this situation over every other coal, notwithstanding its higher price.

“The time during which the gas-light is used may, upon an average of the whole year, be stated at least at two hours per day of 24 hours. In some mills, where there is over work, it will be three hours; and in the few where night work is still continued nearly 12 hours. But taking two hours per day as the common average throughout the year, the consumption in Messrs. Philips and Lee’s mill will be 1250 × 2 = 2500 cubic feet of gas per day; to produce which 700 weight of cannel-coal is required in the retort. The price of the best Wiggan cannel-coal (the sort used) is 13½_d._ per cwt. (22_s._ 6_d._ per ton) delivered at the mill, or say about eight shillings for the seven hundred weight. Multiplying by the number of working days in the year (313,) the annual consumption of coal will be 110 tons, and its cost 125_l._

“About one-third of the above quantity, or say forty tons of good common coal, value ten shillings per ton, is required for fuel to heat the retorts, the annual amount of which is 20_l._

“The 110 tons of cannel-coal, when distilled, produce about 70 tons of good coke, which is sold upon the spot at 1_s._ 4_d._ per cwt. and will therefore amount annually to the sum of 93_l._

“The quantity of tar produced from each ton of cannel-coal is from 11 to 12 ale gallons, making a total annual produce of about 1250 ale gallons, which not having been yet sold, it cannot yet be determined its value.

“The interest of the capital expended in the necessary apparatus and buildings, together with what is considered as an ample allowance for wear and tear, is stated by Mr. LEE at about 550_l._ per annum, in which some allowance is made for this apparatus being made upon a scale adequate to the supply of a still greater quantity of light, than he has occasion to make use of.

“Mr. LEE is of opinion that the cost of attendance upon candles would be as much, if not more, than upon the gas apparatus; so that, in forming the comparison, nothing need be stated upon that score, on either side.

“The economical statement for one year, then, stands thus:

Cost of 110 tons of cannel coal £ 125

Ditto of 40 tons of common ditto, to carbonise 20
----
In all 145
----
Deduct the value of 70 tons of coke 93

The annual expenditure in coal, after deducting the value of the
coke, and without allowing any thing for the tar, is therefore 52

And the interest of capital sunk, and wear and tear of apparatus 550

Making the total expence of the gas apparatus per annum, about 600

“That of candles, to give the same light, would be about 2000_l._ For each candle, consuming at the rate of 4-10ths of an ounce of tallow per hour, the 2500 candles burning, upon an average of the year, two hours per day, would, at one shilling per pound, the present price, amount to nearly the sum of money above-mentioned.

“If the comparison were made upon an average of three hours per day, as in most cases, would perhaps be nearer to the truth, and the tear and wear remaining nearly the same as on the former case, the whole cost would not exceed 650_l._ while that of the tallow would be 3000_l._”

Mr. ACKERMAN in this metropolis, has shown that the art of gas-light illumination is not confined to great manufactories, but that its advantages are equally applicable to those on a moderate scale. The whole of Mr. ACKERMAN’s establishment, his public library, warehouse, printing-offices and work-shops, together with his dwelling house, from the kitchen to the drawing-room, has, for these four years past, been lighted with gas, to the total exclusion of all other lights. The result of the whole of this proceeding will be obvious from the following letter:

To MR. ACCUM.

SIR,

“In answer to your request with regard to my gas-lights, which I now
have in my house, I take this mode of informing you, that I charge two
retorts with 240lbs. of coal, half cannel and half Newcastle, from
which I extract 1000 cubic feet of gas. To obtain this quantity of
gas, when the retorts are cold, I use from 100 to 110lb. of common
coals; but when they are in a working state, that is to say, when they
are once red hot, the carbonising fuel amounts to about 25lb. per
retort. The bulk of gas thus obtained supplies 40 Argand’s lamps, of
the large size, for four hours per night, during the long winter
evenings, together with eight Argand’s lamps and about 22 single
cockspur burners, for three hours per night: in addition to which my
printers employ 16 cockspur burners for ten hours per day to heat
their plates instead of charcoal fire. In the depth of winter we
charge two retorts per day: but, upon an average, we work 365 retorts
in 365 days.

Now 365 retorts containing 120lb. of coal each, make 43800lb. which is
equal to ten chaldrons of Newcastle and eight tons of cannel coal.

10 chaldrons of Newcastle coals, at 65s. make £ 32 10 0
8 tons of cannel coal,[15] (this coal is sold by weight)
at 100s. per ton 40 0 0
7 chaldrons of common coals for carbonising, at 55s. 19 5 0
To wages paid the servant for attending the gas apparatus 30 0 0
Interest of money sunk 30 0 0
The wear and tear of the gas-light apparatus I consider to
be equal to the wear and tear of lamps, candlesticks, &c.
employed for oil, tallow, &c. -----------
Total expence of the gas lights 151 15 0

DEDUCT

23 chaldrons of coke, at 60s. per chaldron 69
Ammoniacal liquor 5
Tar 6
Charcoal employed by the copper-plate printers to
heat their plates, which is now done with the gas-
light flame, cost, annua 25
Two chaldrons of coals _minus_ used as fuel, for
warming the house, since the adoption of the gas-
lights, at 65s. per chaldron 6 10
------ 111 10 0
----------
Nett expences of the gas-lights £ 40 5 0
----------
The lights used in my Establishment, prior to the gas-
lights, amounted annually to 160 0 0
My present system of lighting with gas costs, per ann. 40 5 0
----------
Balance in favor of the gas for one year £ 119 15 0

Such is the simple statement of my present system of lighting, the
brilliancy of which, when contrasted with our former lights, bears the
same comparison to them as a bright summer sun-shine does to a murky
November day: nor are we, as formerly, almost suffocated with the
effluvia of charcoal and fumes of candles and lamps. In addition to
this, the damage sustained by the spilling of oil and tallow upon
prints, drawings, books and paper, &c. amounted annually to upwards of
50l. All the workmen employed in my establishment consider their
gas-lights as the greatest blessing; and I have only to add, that the
light we now enjoy, were it to be produced by means of Argand’s lamps
or candles, would cost at least 350l. per annum.

I am, with respect,

Yours,

Strand, March 13,

1815.

R. ACKERMAN.”

[15] _Although cannel-coal sells at nearly double the price of
Newcastle coal, I use it in preference to the latter, because it
affords a larger portion of gas, and gives a much more brilliant
light._

Another manufacturer who was one of the first that adopted the use of this method of illumination in the small way, and who gave a statement of its advantages to the public, is Mr. COOK, a manufacturer of metal toys, at Birmingham, a clear-headed, prudent man, not apt to be dazzled by a fanciful speculation, but governed in his transactions by a simple balance of profit and loss. There is a _naïveté_ in his own account of the process which will amuse as well as instruct the reader.

“My apparatus is simply a small cast-iron pot, of about eight gallons, with a cast-iron cover, which I lute to it with sand. Into this pot I put my coal. I pass the gas through water into the gasometer or reservoir, which holds about 400 gallons; and, by means of old gun-barrels, convey it all round my shops. Now, from twenty or twenty-five pounds of coal, I make perhaps six hundred gallons[16] of gas; for, when my reservoir is full, we are forced to burn away the overplus in waste, unless we have work to use it as it is made: but, in general, we go on making and using it, so that I cannot tell to fifty or a hundred gallons;--and, in fact, a great deal depends on the coals, some coals making much more than others. These twenty-five pounds of coal put into the retort, and say twenty-five pounds more to heat the retort, which is more than it does take one time with another, but I am willing to say the utmost, are worth four-pence per day. From this four-pence we burn eighteen or twenty lights during the winter season.”

[16] A wine-gallon is equal to 231 cubic inches.

Thus are the candles which Mr. COOK used to employ, and which cost him three shillings a day, entirely superseded. But, besides his expence in candles, oil and cotton for soldering, used to cost him full 30_l._ a year; which is entirely saved, as he now does all his soldering by the gas flame only. For “in all trades in which the blow-pipe is used with oil and cotton, or where charcoal is employed to produce a moderate heat, the gas flame will be found much superior, both as to quickness and neatness in the work: the flame is sharper, and is constantly ready for use; while, with oil and cotton or charcoal, the workman is always obliged to wait for his lamp or coal getting up; that is, till it is sufficiently on fire to do his work. Thus, a great quantity of oil is always burned away useless; but, with the gas, the moment the stop-cock is turned, the lamp is ready, and not a moment is lost.” We must refer to Mr. COOK’s letter for the details of expence, which he gives with faithful minuteness, and always leaning to the side unfavourable to the gas. The result of the whole is, that he saves 30_l._ out of the 50_l._ which his lights formerly cost him: and, when we consider that his calculation allows the gas-lights to burn the whole year, and the candles only twenty weeks, there can be little doubt, that the savings in this case follow nearly the same proportion as in the former. If the apparatus be erected even on a smaller scale, “the saving,” Mr. COOK assures us, “will still be considerable: for the poor man, who lights only six candles, or uses one lamp, if the apparatus is put up in the cheapest way possible, will find it only cost him 10_l._ or 12_l._ which he will nearly, if not quite, save the first year.”

Mr. ACKERMAN having, in this town, set the example of lighting his establishment with gas, several other individuals soon followed the attempt. The following statement will show, that this species of light may be made use of with the greatest advantage, upon a still smaller scale, where no great nicety with regard to the apparatus for procuring gas is required. The following report I have received from Messrs. LLOYD, of Queen Street, Southwark, thimble manufacturers and whitesmiths, who have used the gas-light for soldering and other purposes these five years past.

From 4 pecks or 1 bushel of coals, weighing 69lbs. for
which we now pay (1809) 1s. we produce 4¾ pecks of
coke and ½ peck of coal not carbonised remains in the
distilling pot, which together with the coke weighs
58lbs. 6 oz. value at 1s. per bushel 0 1 4
we procure 6lbs. 4 oz. of tar which we use as pith--it
saves us 0 1 0
----------
0 2 4
Deduct for coal 0 1 0
----------
Profit on coke and tar 0 1 0
----------
The gas yielded by the 4 pecks of coals in the pot, make
42 brilliant lights, which burn 7 hours. To keep 42
tallow candles which were formerly used in the manufactory
burning for the same time, required 7lbs. which at 1s. per
lb. cost 0 7 0
To this, add profits on coke and tar 0 1 0
----------
Gained out of every bushel of coal 0 8 0
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“The gas-burners made use of in our manufactory produce jets of flame, which in our business, where much soldering with the blow-pipe must be done, have a decided superiority over Argand’s lamps. We are not nice concerning the quality of the gas--a great part of it is burned from the gasometer, without allowing it to purify itself in the gasometer, because our gasometer is not large enough to store up the whole quantity of gas we want for use.”

THEORY OF THE PRODUCTION OF GAS-LIGHT, AND DESCRIPTION OF A PORTABLE APPARATUS FOR EXHIBITING, IN THE SMALL WAY, THE GENERAL NATURE OF THIS SPECIES OF LIGHT.

To obtain carburetted hidrogen, or coal-gas, from common pit-coal, and to apply it for the purposes of illumination, the coal is introduced into large iron cylinders, called retorts, to the apertures of which iron pipes are adapted, terminating in a vessel, or vessels, destined to purify and collect the gas. The retorts charged with coals and made air-tight, are placed upon the fire, the action of which extricates the gazeous products from the coals, together with an aqueous ammoniacal vapour, and a tenaceous bituminous fluid, or tar, &c. The liquid substances are conveyed into proper vessels, and the gazeous products are conducted, by means of pipes, under the gasometer, where the gas is again washed, and remains ready for use. There are also other pipes leading from the gasometer, which branch out into smaller ramifications, until they terminate at the places where the lights are wanted. The extremities of the pipes have small apertures, out of which the gas issues, and the streams of gas being lighted at those apertures burn with a clear and steady flame as long as the supply of gas continues. All the pipes which come from the gasometer are furnished at their extremities with stop-cocks to regulate the admission of the gas. The burners are formed in various ways, either a tube ending with a simple orifice, at which the gas issues in a stream, and if once lighted will continue to burn with the most steady and regular light imaginable, as long as the gas is supplied; or two concentric tubes of brass, or sheet-iron, are placed at a distance of a small fraction of an inch from each other, and closed at the bottom. The gas which enters between these cylinders, when lighted, forms an Argand lamp, which is supplied by an internal and external current of air in the usual manner. Or the two concentric tubes are closed at the top with a ring having small perforations, out of which the gas alone can issue, thus forming small distinct streams of light.

The gas-apparatus, plate 2, will be found very convenient for exhibiting, in the small way, the general nature of this new art of illumination, whilst at the same time it may serve to ascertain, at a trifling expence, the comparative value of different kinds of coals intended to be employed for the production of this species of light, as well as other occasional purposes connected with the gas-light system of illumination.

It consists of three distinct apparatus:--namely, a portable furnace, fig. 1, plate 2, by means of which the gas is prepared--fig. 2, a purifyer, or condenser, which separates and purifies the products obtained from the coal, so as to render the gas fit for the purpose of illumination--fig. 3, a gasometer, or reservoir for receiving and preserving the purified stock of gas, and from which it may be transferred and distributed as occasion may require. The following statement will explain more fully the general nature of this portable chamber apparatus:--_a_, represents a cast iron retort, such as is used for chemical operations in the small way. This retort rests upon a tripod of hammered iron, placed upon the bars of the grate of the chemical furnace. Into this retort the coals are put for furnishing the gas. It is provided with a solid iron stopper ground air-tight into the mouth of the retort, and the stopper is secured in its place by an iron wedge passing over it in the centre; by means of which the mouth of the retort when charged with coal is readily made air-tight, and the stopper may easily be removed by knocking out the iron wedge. _b._ is a metal pipe which conveys all the distillatory products from the retort into the purifier fig. 2. This tube is bent at right angles at the extremity where it enters the intermediate vessel fig. 2. The purifier fig. 2, is divided into three compartments marked _c._ _d._ _e._ The first compartment is filled with water, and by means of it an air-tight communication is established with the retort which furnishes the gas. The second compartment, _d_, contains a solution of caustic pot-ash composed of about 2 parts of caustic pot-ash and 16 of water, or a mixture of quick-lime and water of the consistence of very thin cream. The object of this compartment is to separate the non-inflammable gases and other products evolved during the distillation of the coal, from the carburetted hidrogen or coal-gas, so as to render it fit for use. The third compartment _e_ is left empty to receive the tar and other liquid products. Into the first compartment _c_, all the gazeous and liquid products are delivered, as they become evolved during the distillation, by means of the pipe _b_. The compartment _d_, of the purifier, or alcali vessel, is furnished with a wide perpendicular pipe, which serves to make an air-tight communication with the retort, by allowing the tube _b_, to pass readily through it. From the chamber _c_, the liquid and gazeous products pass to the tar-chamber, or compartment _e_, by means of the descending pipe _f_. The tar and other condensible substances are therefore deposited at _e_, whilst the gazeous products alone ascend from the tar-chamber _e_, by the pipe _g_, and down again the pipe _h_, (which is closed at the top) into the compartment _d_, of the vessel or purifier, fig. 2. The gas being thus made to pass from the compartment _e_, up into the pipe _g_, and down the pipe _h_, (which is closed at the top) into the purifier _d_, is brought into contact with the liquor in that vessel, where it is opposed to a pressure in proportion to the perpendicular height of the column of liquid which it contains. The funnel in the compartment _c_, is considerably higher than the purifying apparatus, it therefore allows the liquid which it contains, when pressed upon by the gas, to ascend into it, without overflowing the apparatus, and to descend again as the pressure diminishes--_i_ is another wide-mouth funnel, by means of which the chamber _d_, is filled with the alcaline solution, or mixture of lime and water. The carbonic acid gas and sulphuretted hidrogen, evolved during the distillation of the coal, are thus made to combine with the alcali or lime, in the compartment _d_, of the purifier, forming carbonate and hidro-sulphuret of lime. The carburetted hidrogen, being left more or less pure, is conveyed through the pipe _k_, into the gasometer, fig. 3. The communication of the purifier, fig. 2, with the gasometer, is made by means of the well-known water-valve _l_, placed so that the communicating tube _k_, may be easily removed at pleasure--_m_, is a cock for drawing off the tar, &c. _n_, a gauge-cock for ascertaining the height of the liquid in the chamber _d_. The gasometer, fig. 3, the object of which is to store up the gas, consists of two principal parts--namely, a large interior vessel designed to contain the gas, and an outer cistern or vessel, of rather greater capacity, in which the former is suspended, designed to contain the water by which the gas is confined. The interior vessel which contains the gas is suspended by chains or cords hung over pullies, to which weights are attached, so as to nearly equipoise it. _o_ is a pipe, which communicates with the water-valve _l_, and by means of which the gas passes from the purifier, fig. 2, into the gasometer. The upper end of this pipe is covered, in the manner of a hood, by a cylindrical vessel _p_, open at bottom, but partially immersed beneath the surface of the water contained in the outer cistern of the gasometer, and perforated round near the lower edge with a number of small holes. The gas displaces the water from this receiver _p_, and escapes through the small holes, rising in bubbles through the water, so as to expose a large surface to its action, that it may be properly washed, &c. After rising through the water the gas enters the gasometer, which is suspended to move up and down by the chains, pullies, and balance-weights, _q_. From the centre of the gasometer a tube, _r_, descends, which includes a pipe, _s_, fixed perpendicular from the bottom of the cistern. The fixed pipe _r_, forms a guide to keep the gasometer always perpendicular. _t_ is also an iron pipe made fast in the centre of the inner vessel, and communicates with the upright tube, _s_, in the outer vessel. This contrivance obliges the gas to pass into the pipe _t_, whilst it also serves to keep the gasometer steady when nearly out of the outer cistern.

When the operation commences, the gasometer is sunk down nearly to a level with the surface of the water in the outer cistern, and is consequently filled with water; but as the gas enters, it rises up to receive it. It is to be noted, that the balance-weights _q_ _q_, should not be quite so heavy as the gasometer, in order that some pressure may be exerted, to force the gas out of the burners with a proper jet. The gas which issues from the retort enters the purifier as stated already, and ascends the pipe _o_, into the vessel, _p_, from which it displaces the water, and passes out at the small holes, as before described, rising through the water into the gasometer, and raising it up: the gas then passes away to the burners, _u_ _u_. In this manner the process proceeds until the whole of the volatile products of the coal in the retort is evaporated. The use of the gasometer is, to equalize the emission of the gas which comes from the retort more quickly at some time than others. When this happens, the interior vessel rises up to receive it, and when the stream from the retort diminishes, the weight of the gasometer expels its contents. When the process is finished, the retort is suffered to cool, and its ground stopper is then removed to replenish it with coal. The residue found in the retort is coke. _v_ _v_ are cocks to let off any liquid that may collect in the pipe _o_ or _t_; for if the smallest portion of liquid were to obstruct the free passage of the gas to the burners, the consequence would be, that the lights would not burn steadily--they would, as it is called, _dance_, or become extinguished. _x_ is the main stop-cock which communicates with the burners--these, of course, may be placed as convenience may require. _z_ _z_ are two projecting parts in the top of the gasometer; they are intended to receive the hood _p_, and the upper extremity of the pipe _t_, so as to allow the gasometer to be wholly immersed into the cistern. The wheels or pullies of the gasometer have a groove to allow the links of the chain to pass freely.

In this apparatus there is no provision made for the unequal pressure which the gas suffers, accordingly as the gasometer is more or less immersed in water. It will be observed that, in this apparatus, the weight of the interior vessel is constantly increasing, in proportion as it fills with gas, and rises out of the water, and consequently, if a constant, uniform, counterpoising weight, equal only to that of the gasometer in the first moment of its rise, be employed, the gas becomes gradually more and more compressed by that part of the weight of the gasometer which is not counterpoised, and if its pressure or quantity be then estimated by the bulk which it occupies, without making allowance for the increasing pressure, a material error must arise, and this, in the large way, would give rise to insurmountable difficulties with regard to the regulation of the size of the flames; which could not be rendered uniform.

Suppose the cistern or exterior vessel full of water, and the gasometer partly filled with gas and partly with water, it is evident that the balance-weight may be so adjusted, as to occasion an exact equilibrium, so that the external air shall not tend to enter into the gasometer nor the gas to escape from it; and in this case the water will stand exactly at the same level both within the gasometer and within the outer cistern. On the contrary, if the balance-weights be diminished, the gasometer will then press downwards from its own gravity, and the water will stand lower in the gasometer than it does in the cistern; in this case, the included air or gas will suffer a degree of compression above that experienced by the external air, exactly proportioned to the weight of a column of water, equal to the difference of the external and internal surfaces of the water.

To compensate for this increasing weight of the gasometer, and render a scale of equal graduations accurate, some have ingeniously adopted the plan of a spiral pulley to the chain, which has the effect of gradually avoiding the evil, but the best way of accomplishing it will be stated hereafter.

With regard to the philosophy or the production of coal-gas, it proves that pit-coal contains solid hidrogen, carbon, and oxigen. When the intensity of the heat has reached a certain degree, a part of the carbon unites with part of the oxigen and produces carbonic acid, which by means of caloric is melted into the gazeous state and forms carbonic acid gas; at the same time, part of the hidrogen of the coal combines with another portion of carbon and caloric, and forms the carburetted hidrogen gas, which varies considerably in its constitution, according to the circumstances under which it is produced; a portion of olifiant gas, carbonic oxid, hidrogen, and sulphuretted hidrogen, is also produced during the process. The quantities of these products vary according to the nature of the coal employed in the process.

Pit-coal is not the only substance which affords carburetted hydrogen; this gazeous fluid may be obtained in a great variety of ways, and with very considerable differences in specific gravity and proportion of ingredients.

It is found plentifully native or ready formed on the surface of stagnant waters, marshes, wet ditches, &c. through which, if examined closely, large bubbles will be seen to rise in hot weather, and may be increased at pleasure by stirring the bottom or mud with a stick.

In close still evenings if a lighted candle is held over the surface, flashes of blue lambent flame may sometimes be perceived spreading to a considerable distance. All that is not fabulous concerning the _ignis fatuus_ is probably derived from this source. This species of gas is termed for distinction the carburetted hydrogen of marshes. In the purest form in which it can be collected it is mixed with about 20 per cent. of azot or nitrogen.

To procure the gas for the purpose of philosophical amusement, fill a wide-mouthed bottle with the water of the ditch, and keep it inverted therein with a large funnel in its neck, then with a stick stir the mud at the bottom just under the funnel, so as to cause the bubbles of air which rise from the mud to enter into the bottle; when by thus stirring the mud in various places, the air may be catched in the bottle.

Carburetted hidrogen gas is also given out very abundantly by all kinds of vegetable matter when subjected to a scorching heat sufficient to decompose them. When heated in close vessels much more gas is obtained than when burnt in the open air. If moistened charcoal be put into an earthen retort and heat be applied till the retort becomes ignited; gas will be evolved, consisting partly of carbonic acid, and partly of carburetted hidrogen. A gas of similar properties is obtained by causing steam to pass through a tube filled with red-hot charcoal; by passing spirit of wine, or camphor, through red-hot tubes; by distilling oils, wood, bones, wax and tallow, or any animal or vegetable body whatever.

Indeed it would be endless to enumerate the various sources of this gazeous fluid. A most curious variety of carburetted hidrogen gas has been discovered by the associated Dutch chemists (VAN DIEMAN, TROOSTWYCK, and others) which is procured from ether or alcohol, and has the remarkable property of generating a heavy oil when in contact with chlorine gas. Hence it has been termed oily carburetted hidrogen, or olifiant gas--it consists of carburetted hydrogen, supersaturated with carbon. The oil generated is heavier than water, whitish, and semi-transparent. By keeping, it becomes yellow and limpid; its smell is highly fragrant and penetrating--its taste somewhat sweet--it is partly soluble in water, imparting to it, its peculiar smell. A portion of this gas always accompanies the common carburetted hidrogen obtained from coal, and those sorts of coal that afford the largest quantity of it are best suited for the production of gas-light.